AOD-9604
AOD-9604, explained.
AOD-9604 is an hGH fragment that has been studied in research on fat metabolism — with a more complicated research record than most vendors admit. PepEasy is a place to understand what it is, how it is thought to work, and what its regulatory status actually is, grounded in the published studies.
Educational only — not medical advice. Consult a qualified licensed provider.
AOD-9604 is a synthetic 16-amino-acid peptide based on the C-terminal fragment (residues 177–191) of human growth hormone, with a tyrosine added at the N-terminus. Developed at Monash University as an investigational anti-obesity drug, it was designed to influence fat metabolism without raising IGF-1 or blood glucose like full hGH. It is not FDA-approved.
What AOD-9604 is
AOD-9604 is a lab-made fragment of human growth hormone (hGH). Full hGH does many things in the body — it builds tissue, signals through IGF-1, and influences fat metabolism. Researchers at Monash University in Australia sought to isolate the fat-metabolism portion: the short stretch near the C-terminus of the hormone (amino acids 177–191) that earlier work had tied to lipolysis. They synthesized that 15-residue region and added a tyrosine to the front for stability, producing a 16-amino-acid peptide (sequence YLRIVQCRSVEGSCGF) named AOD-9604, short for 'Anti-Obesity Drug 9604.' It was commercialized by Metabolic Pharmaceuticals and taken into human obesity trials in the 2000s. The research premise was to capture growth hormone's fat-metabolism signal while leaving its growth-promoting and glucose effects behind. Whether it does that in humans is the part the marketing usually skips — and the honest answer, covered below, is that the late-stage trials were disappointing.
How AOD-9604 is thought to work
The proposed mechanism is built on adipose-tissue (fat-cell) biology. In preclinical work, AOD-9604 was associated with increased lipolysis — the breakdown of stored fat — and reduced lipogenesis (new fat storage). The cleanest mechanistic evidence comes from a 2001 mouse study (Heffernan et al., Endocrinology): both hGH and AOD-9604 raised expression of the beta-3 adrenergic receptor (β3-AR), a fat-metabolism receptor on adipocytes, and their weight and fat-loss effects disappeared in β3-AR knockout mice — pointing to that receptor as a critical pathway. In these models AOD-9604 did not raise IGF-1 and did not affect insulin sensitivity or blood glucose the way full hGH can, which was the rationale for using a fragment rather than the intact hormone. Two caveats worth keeping front of mind: most of this mechanistic clarity comes from animals, and demonstrating a mechanism in mice is not the same as demonstrating meaningful fat loss in people.
Areas of research interest
- Body-fat metabolism — the original drug-development target; note the human efficacy data is weak (see Trial results & safety).
- The 'fat metabolism without the hGH downsides' question — research interest stems from the preclinical finding that it did not raise IGF-1 or blood glucose; this is a property observed in the molecule, not a proven clinical benefit.
- Joint and cartilage research — AOD-9604 has also been studied (including in combination formulations) in the context of osteoarthritis/cartilage; this is exploratory and not an approved use.
- GH-secretagogue combinations in community discussion — sometimes paired conceptually with GH secretagogues; such pairing is anecdotal, not evidence-based, and adds unknowns.
Trial results & safety
Across its clinical program — over 900 participants in multiple randomized, double-blind, placebo-controlled trials — AOD-9604 was generally reported as well-tolerated, with no signal of the IGF-1 elevation or insulin-resistance concerns tied to full hGH. The harder truth is on efficacy: a 12-week phase 2b trial in obese adults produced only modest weight loss over placebo, and a longer (24-week) study failed to show a clinically meaningful effect, leading Metabolic Pharmaceuticals to terminate development around 2007. Independent reviewers have argued the pooled human data do not support clinically significant fat loss versus placebo. Separately, FDA has flagged AOD-9604 among peptides that 'may present significant safety risks' for pharmacy compounding — citing limited human data, and potential impurity and immunogenicity concerns for compounded material — and a Pharmacy Compounding Advisory Committee review was scheduled for 2026. The material sold as a research peptide is not a finished, quality-assured drug: purity, sterility, and identity vary by source. Bottom line: the safety record in trials looked clean, but the efficacy case is weak. This is information, not medical advice — talk to a qualified licensed clinician.
Regulatory & legal status
AOD-9604 is not an FDA-approved drug for any use. It is sold almost entirely through research-chemical channels and labeled 'for research use only / not for human consumption,' and as of now it sits outside the cleanly-compoundable peptide list. FDA has identified it among peptides that may present significant safety risks for pharmacy compounding, citing limited human data and impurity/immunogenicity concerns. It is also banned in sport under the WADA S2 category. PepEasy does not sell peptides and does not endorse vendors — this page is neutral education only. Any decision about AOD-9604, and its legal and health consequences, is between you and a qualified licensed clinician.
Frequently asked
Is AOD-9604 a steroid?+
No — it's not a steroid. It's a 16-amino-acid peptide fragment of human growth hormone, designed in research to influence fat metabolism. It is unrelated to anabolic steroids.
What does the research say about AOD-9604 and fat metabolism?+
The human evidence is weak. Early short trials reported modest, statistically-detectable weight differences over placebo, but a longer phase 2b-era study did not show a clinically meaningful effect, and development was terminated around 2007. The animal data on the β3-AR fat-metabolism mechanism is stronger than the human data. This describes the published research record only; it is not a claim that AOD-9604 produces any outcome, and it is not medical advice.
Is AOD-9604 FDA approved?+
No. AOD-9604 is not FDA-approved for any use. FDA has flagged it among peptides that may present significant safety risks for pharmacy compounding, citing limited human data and impurity/immunogenicity concerns. It's sold as a research chemical, not a finished drug. It is also banned in sport under the WADA S2 category.
What's the difference between AOD-9604 and full HGH or other peptides?+
AOD-9604 is just the fat-metabolism fragment of growth hormone — it was studied as a way to influence lipolysis without the growth-promoting, IGF-1-raising, and glucose effects of full hGH. That makes it conceptually different from GH secretagogues like ipamorelin or MK-677, which raise the body's own GH (and downstream IGF-1). It's also unrelated to GLP-1 drugs like semaglutide and tirzepatide, which act through appetite, not direct fat-cell signaling.
Everything peptides, made easy.
Join PepEasy and get the tools, the knowledge, and the care — in one place.
Explore more